JP2006061829A - Micro air-bubble generation apparatus, dissolved oxygen remover using the same and dissolved oxygen removing method using them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a micro air-bubble generation apparatus which has simple structure and can be disassembled for cleaning cleaning, to provide a dissolved oxygen remover using the micro air-bubble generation apparatus and to provide an efficient dissolved oxygen removal method using the micro air-bubble generation apparatus and the dissolved oxygen remover. <P>SOLUTION: The micro air-bubble generation apparatus 1 comprises a throttle part 9 in which the cross-section of a flow path of allowing fluid to flow therethrough is reduced, a divergent part 11 which is located downstream of the throttle part 9 and has the cross-section enlarged along the flowing direction of the flow path, a gas-liquid mixing part 10 which is located downstream of the throttle part 9 and upstream of the divergent part 11 and has a cross-section larger than the cross-section of the throttle part 9, a gas introduction part 14 which is perforated on a pipe body near the constricted part 9, an air chamber formation member 15 which is fitted into a pipe body and forms an air chamber 16 communicated with the gas introduction part 14 and receiving gas from the gas introduction part 14, and a slit part 24 which is located downstream of the throttle part 9 and upstream of the gas-liquid mixing part 10 and introduces the gas radially flowing into the air chamber 16 toward the center line of the pipe. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fine bubble generating apparatus capable of generating fine bubbles, a dissolved oxygen removing apparatus using the same, and a method for removing dissolved oxygen in a liquid using the same.

  Many foods are degraded in quality due to oxidation, and preventing oxidation is very important in maintaining quality. In liquid foods or beverages, dissolved oxygen dissolved in the liquid is one of the causes of oxidation.

  One method of removing dissolved oxygen in a liquid is a degassing method. This is a method of reducing the dissolved oxygen that can be dissolved in the liquid by reducing the pressure in the system containing the liquid to remove the dissolved oxygen. Examples of the degassing method include a membrane degassing method using a gas permeable membrane and a method of spraying a solution in a reduced pressure sealed container.

  Further, a nitrogen substitution method is often used in which nitrogen gas is supplied into the liquid to reduce dissolved oxygen in the liquid. In the nitrogen substitution method, dissolved oxygen moves into nitrogen gas having a low oxygen partial pressure, so that the dissolved oxygen concentration in the liquid is reduced. In this method, in order to efficiently replace nitrogen with a small amount of nitrogen gas, it is necessary to form fine nitrogen gas bubbles or to efficiently mix the liquid and the bubbles. Several techniques have been disclosed for these. For example, a technique has been developed in which a sparger for injecting an inert gas in a radial pattern in a liquid delivery pipe is provided, and the inert gas and liquid ejected from the sparger are mixed efficiently. At this time, in order to refine the inert gas ejected from the sparger, the gas ejection part is made of sintered metal, and in order to further improve the mixing performance of the gas-liquid mixing part, the gas-liquid mixing part is made of metal A device has been devised such as filling with a filling made of (for example, see Patent Document 1).

  A technique for generating fine bubbles in a solution using the ejector effect is also disclosed (see, for example, Patent Document 2 and Patent Document 3). In this method, pressurized water is supplied to a pipe line having a throttle portion, thereby generating a negative pressure portion in the throttle portion and sucking gas to generate bubbles.

In addition, a technique for generating fine bubbles using a swirling fine bubble generator is also disclosed (see, for example, Patent Document 4). This introduces pressurized water in the circumferential direction of the inner wall of the conical container, forms a swirling flow, and ejects this water from the tip of the conical container, thereby forming a negative pressure portion on the conical tube axis. Gas is sucked into the negative pressure portion, and the gas sucked from the upper part of the conical container becomes a string and is ejected together with water from the tip of the conical container. Since the swirling flow is suddenly weakened by the surrounding static water at the same time as the ejection, this is a technique in which the filamentous gas is cut and bubbles of about 10 to 20 μm are generated.
JP 2001-46809 A JP-A-6-63371 JP-A-11-90275 JP 2000-447 A

  The degassing method is a method that can reduce dissolved oxygen by a simple operation as a method for reducing dissolved oxygen, but in the case of removing dissolved oxygen in sake, the alcohol content, aroma component May be removed at the same time.

  Although the method using the ejector effect described in Patent Document 2 and Patent Document 3 can form bubbles by a simple method, the gas is sucked by the liquid introduction action, and the gas-liquid ratio is adjusted. Can not do it. There is also a demand for further miniaturization of bubbles.

  The swirl type fine bubble generator that reduces the dissolved oxygen by generating fine bubbles using the swirl flow described in Patent Document 4 and supplying the fine bubbles into the liquid. Since it is desirable, there are many cases where it is used in a tank.

  For liquid foods, drinking water, alcoholic beverages, etc., it is a method for removing dissolved oxygen that does not impair the aroma components, and the apparatus or method used for it is an apparatus or method that is easy to clean. It is necessary. For this reason, the apparatus used for removal of dissolved oxygen needs to be an apparatus with a simple structure and easy internal cleaning. In terms of ease of cleaning, it is desirable that the dissolved oxygen removing device be installed and used in the middle of the piping.

  An object of the present invention is to provide a fine bubble generating device having a simple structure and capable of being decomposed and washed, a dissolved oxygen removing device using the same, and an efficient method for removing dissolved oxygen in a liquid using the same. .

The present invention relates to a fine bubble generating apparatus for generating fine bubbles by circulating a liquid and a gas through a tube body.
A constricted portion in which the cross-sectional area of the flow path through which the liquid flows is reduced;
A divergent portion that is downstream of the throttle portion and whose cross-sectional area expands in accordance with the flow direction of the flow path;
A gas-liquid mixing section located downstream of the throttle section and upstream of the divergent section and having a cross-sectional area larger than the cross-sectional area of the throttle section;
A gas introduction part drilled in the tube in the vicinity of the throttle part;
An air chamber forming member attached to the inside of the tubular body that communicates with the gas introducing portion and forms an air chamber that receives the gas from the gas introducing portion;
A slit part that is located downstream of the throttle part and upstream of the gas-liquid mixing part, and that introduces gas flowing into the air chamber radially toward the center line of the pipe into the liquid flow path;
It is the fine bubble generator characterized by including.

In the present invention, the tubular body is formed to be separable into two tubular bodies at a substantially central portion,
The microbubble generator according to claim 1, wherein the air chamber forming member is detachably mounted from a tubular body.

In the present invention, the air chamber forming member includes a protrusion at one end,
3. The microbubble generator according to claim 1, wherein the slit portion is formed by bringing a projection of the air chamber forming member into contact with a tubular body. 4.

  Moreover, this invention is provided with the swirl | vortex flow generation | occurrence | production member in the inside of the said pipe body and generating a swirl | vortex flow to the said throttle part upstream, The microbubble in any one of the Claims 1-3 characterized by the above-mentioned. Generator.

The present invention also provides a microbubble generator according to any one of claims 1 to 4,
A nitrogen gas introduction pipe for introducing nitrogen gas for removing dissolved oxygen in the liquid into the fine bubble generating device;
A gas flow meter for measuring a nitrogen gas flow rate provided and introduced in the middle of the nitrogen gas introduction line;
A pressure gauge attached in the middle of the nitrogen gas introduction pipe connecting the gas flow meter and the gas introduction part of the fine bubble generating device;
It is a dissolved oxygen removal apparatus characterized by including.

  Moreover, this invention is the dissolved oxygen removal method using the dissolved oxygen removal apparatus of Claim 5.

  According to the present invention, in the fine bubble generating device for generating the fine bubbles by circulating the liquid and the gas through the tube body, the throttle portion having a reduced cross-sectional area of the flow path for circulating the liquid, and the downstream side of the throttle portion Since there is a divergent part whose cross-sectional area expands according to the flow direction of the flow path, and a gas-liquid mixing part located on the downstream side of the throttle part and upstream of the divergent part and having a cross-sectional area larger than the cross-sectional area of the throttle part, By generating a pressure difference at this portion, fine bubbles can be generated. In addition, an air chamber communicating with the gas introduction portion is formed, and a slit portion is provided for introducing the gas flowing into the air chamber radially toward the center line of the tube into the liquid flow path. It becomes possible to supply the liquid uniformly and has an effect that the bubbles are made finer than the introduction of gas from one place on the circumference.

  Further, according to the present invention, the tubular body is formed to be separable into two tubular bodies at a substantially central portion, and the air chamber forming member is detachable from the tubular body, so that the fine bubble generating device can be easily disassembled. It is. Further, since the air chamber forming member can be detached from the tube body, the inside can be cleaned. This is particularly useful when frequent washing is required, such as in the food field.

  Further, according to the present invention, the air chamber forming member is provided with a protrusion at one end, and the slit portion is formed by bringing the protrusion of the temperament forming member into contact with the tubular body, so that the slit portion can be easily formed. Can do. Further, since the slit width of the slit portion can be adjusted by changing the width of the protrusion, the slit width can be easily adjusted.

  Further, according to the present invention, since the swirl flow generating member that generates the swirl flow is provided inside the tube and upstream of the constriction part, the swirl flow is formed in the liquid upstream of the constriction part, and finer bubbles are formed. Can be generated. In addition, since the swirl flow generating member has a detachable structure, the inside of the tube body can be easily cleaned.

  According to the invention, the fine bubble generating device according to any one of claims 1 to 4 and a nitrogen gas introducing pipe for introducing nitrogen gas for removing dissolved oxygen in the liquid into the fine bubble generating device. Therefore, the fine bubble generating device can be used as a dissolved oxygen removing device. In addition, a gas flow meter for measuring a nitrogen gas flow rate provided in the middle of the nitrogen gas introduction pipeline, and a nitrogen gas introduction pipeline connecting the gas flow meter and the gas introduction part of the fine bubble generator Since the pressure gauge attached in the middle is included, it is possible to easily adjust the nitrogen gas flow rate. Moreover, since this dissolved oxygen removal apparatus is equipped with the microbubble generator comprised including a tubular body, it can be used in the middle of piping. This facilitates disassembly and cleaning operations.

  In addition, according to the present invention, since the dissolved oxygen in the liquid is removed using the dissolved oxygen removing device, it is possible to generate fine bubbles and to remove dissolved oxygen with a smaller amount of nitrogen gas. . Thereby, loss, such as a fragrance component of a food accompanying a dissolved oxygen removal operation, can be controlled.

  FIG. 1 is a simplified cross-sectional view showing a state in which a tubular body of a microbubble generator 1 as an embodiment of the present invention is separated. The fine bubble generating device 1 is a fine bubble generating device that circulates liquid and gas through a tube body and generates fine bubbles by using a pressure change in a flow path.

  The fine bubble generating device 1 includes tube bodies 2 and 3 for circulating a liquid. Each of the pipes 2 and 3 has flanges 4 and 5 at one end, and is used by connecting a gasket 6 between the flanges 4 and 5 and connecting them with a connecting member (not shown). The inside of the tube body 2 has a tapered shape 8 in which the cross-sectional area decreases from the liquid inlet portion 7 toward the liquid flow direction. On the other hand, the tube body 3 has the throttle portion 9 having the smallest cross-sectional area of the flow path on the downstream side where the cross-sectional area decreases in the flow direction, like the tube body 2. A gas-liquid mixing unit 10 having a wider cross-sectional area than the throttle unit 9 is provided on the downstream side of the throttle unit 9, and a divergent part 11 whose cross-sectional area expands in the flow direction is further provided downstream. The taper angle θ1 of the tapered portion 8 and the spread angle θ2 of the divergent portion 11 are preferably about 6 °.

  Here, the flanges 12 and 13 for connecting to other pipe bodies are provided at one end of the pipe body 2 and the pipe body 3, but when the flange is not used for connection to other pipe bodies, the flange 12, 13 is not necessarily required. The connection with the other tube may be a screw mechanism or a tapered tube that can be connected to the other tube.

  The tube body 3 also has a gas inlet 14 for introducing gas in the vicinity of the throttle portion 9. The gas inlet 14 can be formed by making a hole in the tube 3. The tube body 3 includes an air chamber forming member 15 therein. The air chamber forming member 15 forms an air chamber 16 for uniformly discharging the gas introduced into the liquid in the circumferential direction, and the air chamber 16 is connected to the gas inlet 14.

  2 is a side view of the air chamber forming member 15, and FIG. 3 is a view of the air chamber forming member 15 as viewed from the direction of line AA in FIG. The air chamber forming member 15 has a flow path through which the liquid flows, and has a cylindrical shape having a larger outer diameter than the cylindrical member 17, the externally tapered member 18, and the cylindrical member 17. It consists of the member 19 of this. Projections 20 are provided at three positions on the tip of the cylindrical member 17. The number of the protrusions 20 may be one or two. However, since the protrusion 20 functions to determine the width of the slit portion 24, three protrusions 20 are provided in order to make the slit width uniform. desirable.

  The air chamber forming member 15 is detachably mounted from one end of the tube body 3 in contact with the tube body 2, and the air chamber 16 is formed by the inner wall 21 of the tube body 3 and the outer wall 22 of the cylindrical member 17. Since the air chamber forming member 15 has a member 18 having a tapered shape at the center, the air chamber forming member 15 can be easily disposed at the center of the tube body 3. Further, the inner wall of the cylindrical member 17 forms a throttle portion 9.

  Further, in the air chamber forming member 15, the protrusion 20 provided on the cylindrical member 17 abuts on the inner wall 23 of the tubular body 3 to form a slit portion 24. The slit portion 24 communicates with the air chamber 16 and supplies the gas introduced from the gas inlet 14 to the liquid. Since the slit portion 24 is formed uniformly in the circumferential direction, gas can be supplied uniformly in the circumferential direction to the liquid. For this reason, compared with the case where gas is supplied from one place in the circumferential direction, it is possible to supply the gas in a dispersed manner, and the generated bubble diameter can be reduced.

  The width of the slit portion 24 (slit width) is desirably determined in consideration of the relationship with the gas flow rate, and is desirably narrow if the width does not cause a large pressure loss at the time of gas introduction. This is because if the slit width becomes too large, gas cannot be generated uniformly from the circumferential direction. In the present invention, since the slit width is the thickness of the protrusion 20, the slit width can be easily adjusted by changing the thickness of the protrusion 20.

  Further, since the air chamber forming member 15 is detachably attached to the inside of the tube body 3, the air chamber forming member 15 can be removed as necessary. Thereby, the air chamber 16 or the slit part 24 can be easily cleaned. The mounting of the air chamber forming member 15 to the tubular body 3 is not particularly limited as long as it is a detachable mounting method such as mounting by a screw structure or mounting by fitting.

  Furthermore, a spiral swirl flow generating member 25 that generates a swirl flow in the supplied liquid can be mounted inside the tube body 2. FIG. 4 shows a schematic external shape of the swirling flow generating member 25. The swirl flow generating member 25 has a diameter substantially coincident with the tapered shape 8 of the tube body 2, and a twist of 180 ° is added to generate the swirl flow. Thereby, a swirl flow is generated in the liquid, and finer bubbles can be generated. The shape of the swirl flow generating member 25 is not particularly limited as long as it has a function of generating a swirl flow. Further, since the swirl flow generating member 25 is detachably mounted, the inside of the tube body 2 can be easily cleaned by removing it.

  Next, the operation of the fine bubble generator 1 of the present invention will be described.

  The liquid is supplied to the liquid inlet portion 7 of the microbubble generator 1 by a liquid supply pump (not shown) or the like. The supplied liquid flows into the tube 3 while increasing the liquid flow rate because the cross-sectional area of the tube 2 decreases in the flow direction. The liquid flowing into the tube body 3 further increases the liquid flow rate at the throttle portion 9 having the smallest cross-sectional area. In the throttle unit 9, the liquid flow is maximized while the static pressure is lowered. The liquid that has passed through the throttle unit 9 decreases the liquid flow rate at the gas-liquid mixing unit 10 having a larger cross-sectional area than the throttle unit 9 and simultaneously increases the static pressure, and then flows into the divergent unit 11.

  On the other hand, the gas is supplied at an arbitrary flow rate through a gas supply pipe (not shown) connected to a gas inlet 14 provided in the vicinity of the throttle 9. The supplied gas is guided from the gas inlet 14 to the air chamber 16, and the gas flows out from the slit portion 24. Since the slit portion 24 is provided at the boundary between the throttle portion 9 and the gas-liquid mixing portion 10, the inflowing gas generates a shearing force due to a pressure difference between the throttle portion 9 and the gas-liquid mixing portion 10. Become. Since the slit part 24 is provided uniformly in the circumferential direction, the gas flows out uniformly from the circumferential direction. Thus, since the gas introduced from one place is discharged | emitted uniformly on a periphery, a fine bubble can be generated.

  Next, the dissolved oxygen removal apparatus 30 using the said microbubble generator 1 is shown. FIG. 5 is a diagram showing a schematic configuration of a dissolved oxygen removing apparatus 30 using a fine bubble generating apparatus 1 as another embodiment of the present invention. In this embodiment, parts corresponding to those of the embodiment of FIG. The dissolved oxygen removing device 30 is generally composed of a fine bubble generating device 1, a nitrogen gas supply system 40, and a mount 50. The nitrogen gas supply system 40 includes a micron filter 41, a deodorizing filter 42, a nitrogen gas flow meter 43 and a pressure gauge 44.

  Nitrogen gas supplied through a nitrogen gas cylinder (not shown) or the like is introduced through an inlet 46 that is one end of a resin-made nitrogen gas introduction pipe 45, and fine foreign matters are removed by the micron filter 41. Nitrogen gas from which foreign matter has been removed by the micron filter 41 flows into the deodorizing filter 42 where it is deodorized. In the present embodiment, resin pipes are used for the nitrogen gas introduction line 45, but it goes without saying that stainless steel pipes may be used. The deodorizing filter 42 has a fixing member 51 attached to the deodorizing filter 42, and the fixing member 51 is joined and fixed to the mount 50 with a joining member 52 such as a screw.

  The micron filter 41 and the deodorizing filter 42 are not necessarily used, and may be properly used according to the usage application of the dissolved oxygen removing device 30. For example, when removing the dissolved oxygen in the drainage liquid, it is not necessary to use the micron filter 41 and the deodorizing filter 42, but the dissolved oxygen removing device 30 is used for removing the dissolved oxygen from the liquid food or beverage. In such a case, it is desirable to use the micron filter 41 and the deodorizing filter 42. The nitrogen gas that has passed through the deodorizing filter 42 is introduced into the gas inlet 14 of the fine bubble generating device 1 through a nitrogen gas flow meter 43 fixed to the gantry 50. The nitrogen gas introduction pipe 45 and the gas introduction port 14 are connected by a connection member 46 such as a fitting.

  The nitrogen gas flow meter 43 is provided with a flow rate adjusting valve 47, whereby the amount of gas supplied can be adjusted. Further, a pressure gauge 44 is provided in the middle of the nitrogen gas introduction pipe line 45 connecting the nitrogen gas flow meter 43 and the gas introduction part 14, and the pressure in the pipe line can be confirmed. Further, in order to protect the nitrogen gas flow meter 43 or the pressure gauge 44, a check valve for preventing the back flow of the liquid is provided in the middle of the nitrogen gas introduction pipe line 45 connecting the pressure gauge 44 and the gas introduction part 14. It is desirable to provide it. The fine bubble generator 1 is fixed to the gantry 50 using a solid member (not shown).

  When the present dissolved oxygen removing device 30 is used with the above-described configuration, a liquid supply pump or the like is connected to the inlet of the microbubble generator 1 to supply the liquid, and the nitrogen gas inlet 46 Nitrogen gas is supplied through and used. The fine bubble generating device 1 can generate fine bubbles in the liquid, and can efficiently remove dissolved oxygen in the liquid with a small amount of nitrogen gas. Since the present dissolved oxygen device 30 can be installed and used in the middle of the liquid supply piping, the device can be easily disassembled and cleaned.

  Although the use destination of this dissolved oxygen removing device 30 is not particularly limited, water for food processing, alcoholic beverages such as sake, wine or shochu, soft drinks such as juice, seasonings such as soy sauce, liquid food such as edible oil, liquid If it is used for a cosmetic, dissolved oxygen in the liquid can be removed with almost no discharge of aroma components. Furthermore, since the decomposition and washing are easy as described above, the dissolved oxygen removing device 30 can be suitably used for foods and beverages.

  In this embodiment, an example in which nitrogen gas is used to remove dissolved oxygen is shown, but the gas that can be used to remove dissolved oxygen is not limited to nitrogen gas. An inert gas such as carbon dioxide or argon gas can be used depending on the intended use.

  Next, the Example using the dissolved oxygen removal apparatus 30 is shown.

  In Example 1, dissolved oxygen contained in the liquor being stored was removed using the dissolved oxygen removing device 30. FIG. 6 shows a process flow for removing oxygen according to the first embodiment. The general liquor stored in the low temperature storage 60 was sent through the liquid pump 61 to the fine bubble generating device 1 constituting the dissolved oxygen removing device 30 at a rate of 100 liters per minute. Nitrogen gas was provided with a pressure reducing valve 63 at the outlet of the nitrogen gas cylinder 62, the flow rate was adjusted to 30 liters per minute with the needle valve 64, and the nitrogen gas was supplied to the fine bubble generator 1. The nitrogen gas flow rate and pressure were confirmed with the nitrogen gas flow meter 43 and the pressure gauge 44 of the dissolved oxygen removing device 30. The liquor from which dissolved oxygen was removed through the fine bubble generator 1 was stored in the room temperature storage 65. The temperature of the low temperature storage 60 was about 2 ° C., and the normal temperature storage 65 was at room temperature.

  In order to examine the amount of change in the fragrance component accompanying the removal of dissolved oxygen, the concentration of the fragrance component was measured when the dissolved oxygen removal operation was performed and when the dissolved oxygen removal operation was not performed. As the aroma component, isoamyl acetate and ethyl caproate, which are representative aroma components of sake, were selected, and the concentration was measured by gas chromatography.

  (Results of Example 1) The concentration of dissolved oxygen contained in the sake in the room temperature storage 65 immediately after the transfer of 4000 liters of liquid was 0.8 mg / L. At this time, the replacement efficiency of dissolved oxygen and nitrogen gas was almost 100%. The concentration of isoamyl acetate contained in the liquor after the dissolved oxygen removal operation was about 2.73 mg / L, whereas the concentration of isoamyl acetate when the dissolved oxygen removal operation was not performed was about 2.69 mg / L. And almost the same value. Similarly, the concentration of ethyl caproate contained in sake is about 1.42 mg / L when the dissolved oxygen removal operation is performed, and about 1.30 mg / L when the dissolved oxygen removal operation is not performed. there were.

  The example at the time of using ginjo sake is shown.

  The conditions are the same as in Example 1 except that the storage temperature of the low-temperature storage 60 was 13 ° C. and the amount of liquor transferred was 550 L. In Example 2, only the analysis of aroma components was performed.

  (Result of Example 2) The concentration of isoamyl acetate contained in the sake after the dissolved oxygen removal operation was about 1.70 mg / L, whereas the concentration of isoamyl acetate when the dissolved oxygen removal operation was not performed was The value was almost the same as about 1.83 mg / L. Similarly, the concentration of ethyl caproate contained in sake is about 1.08 mg / L when the dissolved oxygen removal operation is performed, and about 1.22 mg / L when the dissolved oxygen removal operation is not performed. there were.

Comparative Example 1

  A microbubble generation test was performed under the following conditions using a microbubble generator of a type in which nitrogen gas is supplied from one place in the circumferential direction as conventionally used. The diameter of the throttle part was 6 mm, the liquid supply liquid amount was 2000 liters per hour, and the supply gas amount was 10 liters per minute.

  (Result of Comparative Example 1) The pressure on the gas side was not sufficiently reduced, and the bubbles were not sufficiently refined.

It is a simple sectional view showing the state where the tube of fine bubble generating device 1 as one embodiment of the present invention was separated. It is a side view of the air chamber forming member 15 of the present invention. It is the figure seen from the direction of the AA line of FIG. 2 of the air chamber formation member 15 of this invention. It is a figure which shows the general | schematic external appearance shape of the swirl | vortex flow generation member 25 of this invention. It is a figure which shows schematic structure of the dissolved oxygen removal apparatus 30 using the microbubble generator 1 as other form of implementation of this invention. It is a figure which shows the schematic flow of the oxygen removal of Example 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fine bubble generator 2, 3 Tubing body 9 Restriction part 10 Gas-liquid mixing part 11 Wide end part 14 Gas introduction part 15 Air chamber formation member 16 Air chamber 20 Projection 24 Slit part 25 Swirling flow generation member 30 Dissolved oxygen removal apparatus 43 Gas flow meter 44 Pressure gauge 45 Nitrogen gas inlet line

Claims (6)

In a fine bubble generator that circulates liquid and gas through a tube to generate fine bubbles,
A constricted portion in which the cross-sectional area of the flow path through which the liquid flows is reduced;
A divergent portion that is downstream of the throttle portion and whose cross-sectional area expands in accordance with the flow direction of the flow path;
A gas-liquid mixing section located downstream of the throttle section and upstream of the divergent section and having a cross-sectional area larger than the cross-sectional area of the throttle section;
A gas introduction part drilled in the tube in the vicinity of the throttle part;
An air chamber forming member attached to the inside of the tubular body that communicates with the gas introducing portion and forms an air chamber that receives the gas from the gas introducing portion;
A slit part that is located downstream of the throttle part and upstream of the gas-liquid mixing part, and that introduces gas flowing into the air chamber radially toward the center line of the pipe into the liquid flow path;
A microbubble generator characterized by comprising: The tubular body is formed to be separable into two tubular bodies at a substantially central portion,
The microbubble generator according to claim 1, wherein the air chamber forming member is detachably attached to the tube body. The air chamber forming member includes a protrusion at one end,
The fine bubble generating device according to claim 1, wherein the slit portion is formed by bringing a projection of the air chamber forming member into contact with a tubular body.   The fine bubble generating device according to any one of claims 1 to 3, further comprising a swirl flow generating member that generates a swirl flow inside the tubular body and upstream of the throttle unit. The fine bubble generator according to any one of claims 1 to 4,
A nitrogen gas introduction pipe for introducing nitrogen gas for removing dissolved oxygen in the liquid into the fine bubble generating device;
A gas flow meter for measuring a nitrogen gas flow rate provided and introduced in the middle of the nitrogen gas introduction line;
A pressure gauge attached in the middle of the nitrogen gas introduction pipe connecting the gas flow meter and the gas introduction part of the fine bubble generating device;
A device for removing dissolved oxygen, comprising:   A dissolved oxygen removing method using the dissolved oxygen removing apparatus according to claim 5.

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